Powdered pigment compositions



Patented Oct. 7, 1952 UNITED STATE "rownnnnn PIGMENTCOMPOSITIONS WilliamT. Walton, Chicago, Ill., and Arthur B. Holton, Bay Village, Ohi,assignors to The Sherwin-Williams Company, Cleveland, Ohio, acorporation of Ohio No Drawing. Application March 29, 1950, Serial No.152,765

This inventionl relates to powdered pi ment compositions, to methods forthe preparation thereof, and to a new, and improved method for thehandling and application of pigments and vehicles therefor. a v 1 It. iscustomary at the present time for the manufacturer to .mix pigmentsdirectly with suit able vehicles in order to supply the user with acomplete line of readymixedpaints, enamels, or lacquers, of differentcolors. With the usual pigments and vehicles the proper dispersion ofthe pigment in the vehicle ordinarily requires expert skill andapparatus which is not possessed by the average user. This procedure inthe prepara'- tion and handling of paint and other pigmented vehicleshas the disadvantages that a wide variety of paint compositionsmust becarried in stock over relatively long periods of time, and the totalquantity or bulk of paint in storage is necessarily very large. Thedemand for some color is naturally much greater than for others so thatthe colors for which there is little demand will stand; on theshelves-of the paint shop or in a warehouse over a considerably longerperiod of time than the cftherssv As a result, the pigments tend tosettle, skin s,tend to form onthesurface of the paint, and special meansmust be provided in some cases to. redisperse the pigments and toprevent the formation of such skins.

One of the objects of the present. invention is to provide anewand-i-mproved system or procedure/for the preparation and applicationof paints. enamels and other pigmented coating compositions wherein thehandling and distribution of the compositions and the ingredientsthereof are greatly facilitated.

Another object of the inventionis. to provide a new and improved] pluralcomponent pigment composition comprising 'on the one ha d a pi mentpreparation of a "predetermined color adapted to be dispersed in asuitable vehicle, and, on the other hand',a pigmented vehicle in whichthe aforementioned pigment preparation can be dispersed by the ordinary--user merely with hand stirringand without'the necessity for employingspecial apparatus or equipment such as is used by paint manufacturers atthe present time in order to disperse. pigments in vehicles.

A further object of the invention is to provide a new and improvedpowdered pigmentcomposition which is readily dispersible by handstirring in suitable vehicles to produce paints, lacquers and otherpigmentedvehicles- A more specific object of the invention; is toprovide new and improved powdered pigment- 18 Claims. (01. 106-218) 2resin compositions which are readily dispersible in liquid vehicles, andare characterized by full color development merely by hand stirringwithin a relatively short time. Other objects of the invention willappear hereinafter.

In accordance with this invention, it hasbeen found that by millingresins with pigments in certain predetermined proportions new andimproved pigment compositions are obtained which, when reduced to aproper particle size, are dispersible in the ordinary type of paint,enamel or lacquer vehicle merely by hand stirring toproduce ubstantiallyfull color development within a relatively short time.

l-Ieretoiore resins have been mixed with pigments, but, in general, theratio of resin to pigment has been rather small, usually on the order ofabout 2% to about 5%. The amounts used have been calculated to producefilms on the pigment particles on the order of a monomolecular film, andone reason for keeping the amount of resin low'has been the desire totreat the pigment in such a way that its tinting properties are notaffected.

In the practice of this invention, it has been found that small amountsof resins applied to pigments actually defeat the purpose of theinvention, but that by milling a resin with a pigment in predeterminedrelatively large proportions of resin to pigment, new and improvedpigment-resin compositions are obtained which can be very readilydispersed in a suitable vehicle with excellent color development merelyby hand stirring. The amount of resin required for optimum results willvary omewhat with different pigments, but with each type of pigmentthere is a determinable minimum amount of resin to pigment, below whichthe desired results are not obtained. The amount of resin requiredappears to be related to the surface area of the pigment, and based uponthe results obtained with various pigments it is apparent that theamount of resin required is substantially greater than that required toproduce a monomolecular film or coating of the resin on the pigmentparticles.

Verbyla, in U. S. 2,00,003 has disclosed a dispersion of a pigment in aresin, the product being in the form of lumps or small pieces; Whilesuch, product is dispersible in paint systems, a relatively long periodof agitation is requisite to hand or manual dispersion. The time factoris believed to confine use of the 'Verbyla system principally to factoryapplication Where power mixing equipment is available. In order toobtain the rapid dissolution characteristics essential to a colorconcentrate for home use and manual stirring, we have discovered thatthe proportion of pigment dispersed in the total pigment-resincombination must be correlated with the average or mean particlediameter and the specific gravity of the pigment, and furtherclassification of the particle size of the pigmentin-resin product mustbe made, retaining the. particles for use in color concentrates within arelatively narrow range of particle size. It is believed that thefailure of the prior art to recognize these critical factors has beeninstrumental in retarding public acceptance of a'liry powdered colorconcentrate for custom color mixing at home, and that the productdisclosed, because it is rapidly dispersible by manual stirringovercomes the principal objection to prior solid color concentrates.

Pigments are classified herein in terms of particle size and specificgravity, that is, surface area per pound, as small, medium and large.Chrome Yellow and Chrome Green are examples in the first category, IronBlue an example of the second category, and Lampblack and Monastral Blueare examples of the third category. In terms of particle size, thepigments in the first category have a particle size (diameter asmeasured by the photographic method of Green) withinthe-range from 0.3to 0.5 micron, in the second category from 0.2 to 0.3 micron, and in thethird category from 0.08 to 0.2 micron. (See Table A, column 11.) Thepredetermined critical minimum weight ratio of resin to pigment in thepowdered pigment composition, based upon total weight of resin andpigment, will vary from about resin for pigments having surface anddensity characteristics in the first category to 65% for pigments in thethird category, as'will be more fully illustrated hereinafter in theexamples.

It has also been found, in accordance with the invention, that the colordevelopment is affected by the particle size of the powderedresin-pigment composition even though the ratio of resin to pigmentremains constant and that the best results are obtained within apredetermined range of resin-pigment particle size. Within saidpredetermined range of resin-pigment particle size the optimum colordevelopment is obtained in a minimum period of manual stirring. Withtheoptimum predetermined preferred ratio of resin to pigment, theoptimum particle size for maximum color development in a minimum periodof time is about the same regardless of the type of pigment, ashereinafter shown in the examples.

Another important feature of the invention resides in the use of resinswhich may be characterized as high melting. High melting resins arepreferred so that the granules of material remain discrete and do notstick or flow together under storage at. normal temperatures, or eventhe highest temperatures under which the product might be stored. Itwill be understood that there may be some softening of the resin beforethe melting 'temperature is reached. The resin, however, must show nosubstantial softenin at atmospheric temperatures, and preferably shouldnot soften or start to melt at temperatures below 100 degrees C. Resinsmelting around 130 degrees C., or higher (ball and ring method) arepreferred, although it will be understood that resins having a somewhatlower melting may be used where storage conditions are not adverse.Thus, Velsicol AB-11-4 (melting point 112.8-

.4 118.3 degrees C.) produces an entirely satisfactory product for mostpurposes, as hereinafter described. The resin employed for coating thepigment particles should be soluble in the liquid vehicle, in which theresin-pigment composition is to be dispersed.

To demonstrate the invention a series of test resin-pigment compositionswere prepared. In each case a suitable resin and a pigment were milledtogether on a 2-roll rubber mill, one roll of whichwas heated by steamto a temperature which permitted easy milling (20 to 45 pounds gage),the other roll being cold. One roll rotated faster. than the other. Theresin-pigment ratio was changed in successive runs in steps of 10 unitsof percentage composition,except at thelow resinpigment ratios wheredifficulty was encountered in milling. In these regions the compositionwas altered more gradually. The resin-pigment composition adhered to thehot roll from which it was cut and re-milled from time to time. Themilling was continued until a glossy chip, or mirror-like appearance,was obtained, thereby indicating that the pigment was coated with theresin since it no longer had a flat appearance.

The milled resin-pigment mixture was allowed to cool in a thin sheet,was then broken up manually and passed once through a micropulverizer toproduce powdered resin-pigment compositions.

The colored pigments chosenwere Toluidine Red, Monastral Blue,Lampblack, Prussian Blue, Red Iron Oxide, Ferrite Yellow, Light ChromeGreen, and ChromeYellow. The resins used for coating each of thesepigments in the manner previously described on a 2-roll rubber mill werea pentaerythritol ester of a rosin-maleic anhydride addition productsold under the name Pentalyn G, and a' resinous hydrocarbon condensationproduct obtained by the polymerization of recycle stock derived as aby-product of oil cracking, the polymerization being effected by theFriedel-Crafts' method in the presence of aluminum chloride sold underthe name Velsicol ABM-4;. Recycle stock is a petroleum fractionboiling'within the range of about 200 degrees to about 450 degrees F.comprising olefins and diolefins both straight chain and cyclic innature and derived from the high temperature cracking of naphtha and gasoil fractions. The latter had a specific gravity Within the range from1.090 to 1.120, a melting point of 235 degrees F. to 245 degrees F. bythe ball and ring method, an iodine number of 65 to by the Wijs method,an acid number of 5 or less, and a color of 4 (Barrett). Both resinswere soluble in aliphatic petroleum solvents.

In testing the resin-pigment compositions, two white enamels were usedand a predetermined weight of colored resin-pigment composition wasadded to a predetermined weight of each type of enamel in the mannerpreviously described. Each enamel contained 1.75 pounds of rutiletitanium dioxide (white pigment) per gallon of enamel. One of theseenamels, referred to as enamel A, had an oleoresinous varnish as avehicle in which the resin was a pentaerythritol ester of rosin and theoil was dehydrated castor oil, this varnish being 25 gallons in length,that is to say, it contained 25 gallons of oil per pounds of resin, orapproximately two pounds of oil per pound of resin.

The vehicle of the second enamel, referred to herein as enamel B, was analkyd varnish which contained 21% phthalic anhydride and 29% of avegetable oil composed of equal parts of linseed oil and alkali refinedsoya bean oil.

The various pigment-resin compositions pre: pared as previouslydescribed were added to 200 grams of each enamel in proportions suchthat the weight of colored, pigment was the. samein each test within agiven series. Therefore. if

idine Red and theresiirwas, Velsicol AB11-4. The proportion of theresin-pigment composition added to white enamelsA and B corresponded to1.5 gramsof colored pigment per 200 grams of each enamel.

' The results obtained are illustrated in the following table:

Table I Percent Pigment 30. 4O 50 60 70 Percent Resin 90 80 70 6O 50 40Poor Poor Poor Poor Poor Poor Poor Fair Fair Good Fair Fair Poor PoorGood I Good Good Good Good Poor Poor K. O. K. O. K. 0. K. O. K. PoorPoor KL 0. K. 0. K. 0. K. O. K. Poor Poor K. O. K. O. K. O. K. O. K.Poor Poor K. O. K. O. K. O. K. O. K. Poor Poor K. O. K. O. K. O. K. O.K. Poor Poor K1 0. K. O. K. O. K. i O. K. Poor Poor K. O. K. O. K. 0. K.0. K. Poor Poor the dispersion of the colored pigment was equal and thedispersibility of the: pigment-resin dispersion. was complete, the. sametint was produced in each case.

The various pigment-resin dispersions were equally dispersible in the'oleoresinous and the alkyd enamels. in the latter than in the former.

Since the results were substantially similar with enamels A and B, itwill be understood that in each of the following examples. the tablesgiven are. applicable to both types of white enamel when. employed inconjunction with the given colored pigment-resin composition.

The dispersibility of each series of powders. was tested by stirringinto a white enamel such weights of the powders as contained equalweights of pigment. Stirring was manual, but timed at approximately 120.strokes per minute. At the end of each minute, a few drops of themixture were placed on a non-porous White paper, pressed and drawn downwith axbroad spatula. The dispersibility was deduced from the degree ofstreaking and tabulated.

At the end of 10 minutes stirring, thenow pigmented enamel was brushedout on paper, and a .005" film drawn down with a gage. The oomparative.depths of color in the brushed out-and drawn down films gavea secondcriterion of dispersibility.

The results are shown in the following ex- They dispersed slightlyfaster amples, in which the percentages are given in parts by weight.The first column in each table in the examples gives the time ofstirring in minutes. evaluation of dispersibility or color developmentfor difierent resin-pigment compositions at intervals of one minute toten minutes from the time that the resin-pigment composition was addedto the white enamels A and B.

EXAMPLE I p In this example the colored pigment was Tolu- Eachsucceeding column represents an.

As shown in this table the critical minimum ratio of resin. toplgmentrwith this particular pigment was 50% by weight of resin and 50%by weight of pigment. The optimum'ratio appeared to be at 70% resin to30% pigment. Poor results were obtained with resin and 60% pigment, thusdemonstrating that there is a critical minimum ratioof resin-to pigment.

EXAMPLE II.

In this example the colored pigment was Toluidine Red and the resin was.Pentalyn The proportion of the resin-pigment compositionadded to whiteenamels A and B corresponded to 1.5 grams of colored pigment per 200grams of each enamel. p i

The results obtained with compositions containing different ratios ofresin to pigment are illustrated in the following table:

Table II 1 Percent Pigment..." 10 v 20 so 40 5c 60 Percent Resin 9O 8O70 60 I 40 Poor Poor Fair Fair Fair 0. K. K. i0. K. Fair 0. K. O. K. O.K. Good O. K. O. K. O. K. O. K. O. K. 0. K. 0. K. O. K. O. K. O. K. 0.K. O. K. O. K. O. K. O. K. O. K. O. K. O. K. O. K. O. K.

In this example the colored pigment was Chrome Yellow and the resin wasV elsicol ABl 1-4. The proportion of the resin-pigment composition addedto white enamels A and B corresponded to 3 grams of colored pigment per200 grams of each enamel.

v The results obtained with compositions containing different ratios ofresin to pigment are illustrated in the following table:

Table III Percent Pigment 10 20 30 1 40 50 Percent Resin 80 70 6O 5O 4030 2O Poor Poor O. K. O. K. O. K. O. K. O. K. Poor Poor 0.1K. v 0. K. O.K. O. K. 0.1K. Poor Poor O. K. O. K. 0. K'. 0. K. O. K. Poor 0. K. O. K.0. K. O. K. O. K. Poor 0. K. O. K. O. K. 0. K. O. K. Poor 0. K. O. K.O.K. O. K'. .O. K'. Poor 0. K. 1K. 0..K.v 0.,K. O. K. Poor 0. K. O. K.O. K. O. K. O. K. Poor 7 EXAMPLE IV taining difierent ratios of resin topigment are illustrated in the following table:

Table IV Percent Pigment. 30 40 50 60 Percent Resin 90 80 70 6O -50 40Poor Poor Poor Poor Poor Poor Fair Fair Good Fair Fair Poor Good Good 0.K. Good Fair Poor K. O. K. O. K. O K. O. K Poor 0. K. O. K. O. K. O. K.O. K. Poor 0. K. O. K. O. K. O. K. O. K. Poor 0. K. O. K. O. K. O. K. O.K. Poor 0. K. O. K. O K O. K. O. K. Poor 0. K. 0. K. O. K. O. K. 0. KPoor 0. K. O. K. O. K. O. K. O. K. Poor EXAMPLE V taining differentratios of resin to pigment are illustrated in the following table:

Table V Percent Pigment 10 i Percent Resin 90 I 80 70 The proportion ofthe resin-pigment Table VI Percent Pigment 10 20 Percent Resin 90 80 706O 50 1 min Poor Poor 2 min-.- Poor Poor 3 min- Poor Poor Poor Poor PoorPoor Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor EXAMPLE VII Inthis example the colored pigment was Light Chrome Green and the resinwas Velsicol AB11-4. The proportion of the resin-pigment compositionadded to white enamels A and B corresponded to 2 grams of coloredpigment per 200 grams of each enamel.

The results obtained with compositions containing difierent ratios ofresin to pigment are illustrated in the following table:

Table VII Percent Pigment. 30 40 50 7O 80 Percent Resin 60 5O 40 30 20Poor Poor Fair Poor Poor Poor Fair Fair Good air Fair Poor Fair Good 0.K. Good Good Poor 0. K. 0. K. O. K. O. K. 0. K. Poor 0. K. O. K. O. K.O. K. O. K. Fair 0. K. O. K. O. K. O. K. O. K. Fair 0. K. O. K. O. K. O.K. O. K. Fair 0. K. O. K. O. K. O. K. O. K. Fair 0. K. O. K. O. K. O. K.O. K. Fair 0. K. O. K. O. K. 0. K. O. K. Fair EXAMPLE VIII In thisexample the colored pigment was Ferrite Yellow and the resin wasVelsicol AB11-4. The proportion of the resin-pigment composition addedto white enamels A and B corresponded to 3 grams of colored pigment per100 grams of each Table VIII Percent Pigment 10 20 30 40 50 60 PercentResin 90 8O 70 60 50 4O 20 10 Poor Poor Poor Poor Poor Poor Poor PoorPoor Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor EXAMPLE VIIn this example the colored pigment was Lampblack and the resin wasVelsicol ABll-el. The proportion of the resin-pigment composition addedto white enamels A and B corresponded to gram of colored pigment per 200grams of each enamel.

The results obtained with compositions containing different ratios ofresin to pigment are illustrated in the following table:

EXAIVEPLE IX 'Table IX Percent Pigment 3O v L ,70 80 Percent Resin 90 8070 60 50 510; 30 '20 Poor Poor Poor Poor Poor Poor Poor Fair Fair FairPoor Poor Fair Fair Fair 0. K. Fair Fair 0. K. O. K. O. K. 0. K.. Good;Fair 0. K. O. K. 0. K. 0. K. O. K. Good 0. K. O. K.- 0. K. i O. K. .OJK.Good 0. K. O. K. O.'K. 0. K. O. K. K.

O. K. O. K. O. K. O. K. O. K. O. K.

O. K. 0. K. O. K. 0. K. O. K. O. K.

O. K. O. K. O. K. O. K. O. K. 0. K.

taming different ratios of resin to pigment are 15 illustrated in thefollowing table: In this example the colored pigment a Table 1 MonastralBlue and the resin was Pentalyn G. I i The pl'flpoltltln f h r n-p g pQ$Qn Percent pigment 0 20' 30 35 added to whlte enamels A and Bcorresponded PercentBesin.-.. 90 so 70 to 1 gram of colored pigment per200 grams of Poor Poor Poor each enamel. Fair Fair Pool. The resultsobtalned with compositions con- GFaig good Fair taining different ratiosof resin to pigment are ff; fig O.K 0 K. 0.1:. lllustrated 1n thefollowmg table. Q QK T bl X 1%. 101K1 1 2 03;:

Percent Pigment 10 20 25 7 Percent Resin 90 .30 75 6O U :In h s examp th:colore net-e99? was 338; $33; $33; Chrome Yellow and the resin wasBentalyn m m P t Th nreper iqne ther sineniem ei. pesii 89;? 8255 53;;added t white enamels 11 1Bs9r e 9 ed 0.x. 0. K. Fair 35 to 3 grams ofcolored p i g-mentper 200 .g ms 8% 8 gggg of each enamel. 0.1;, 0,11,Good The results obtained with compositions containi-ng different ratiosof resin to pigment are illustrated in the following table:

fable .XI

Percent Pigment 10 1 20 so 40 .50: e0 l Percent Resin. 9O 70 6O .50. 4030 =25 Poor Poor Poor Poor Fair Fair Fair 'Poor Good Fair .Fair Jiair 0.0. .K. Good 0. K. Goon o- 0. K. 0. K. 0. K.. TGo'od o. 0. K. 0. K. 0. K.0. K. 'o. 0; K. 0; K. 0; K. 0. K. o. 0. K. 0. .K. 0. K. 0. K. 1 o. 0.K.:05K; IQJK. .0. K.

1. K- -.-.K-:- D4

;I. this exampl th .eel red P men wa Fer it Yel w a d th r sin wa.Iienie y The proportion of the resin-pigment composie In this examplethe colored pigment was Lampblack and theresin-Was Pentalyn G. The

proportion of the resin-pigment composition added to white enamels A andB corresponded to gram of colored pigment per .ZQdgrams of each enamel.

The results obtained with compositions contion added to white enamels Aand *B corresponded to 3 gramsof colored pigment per 200 grams of eachenamel.

The results obtained with compositionscontainlng different ratios ofresin to pigment are illustrated in the following-table:

.11 EXAMPLE XIV In this example the colored pigment was Prussian Blueand the resin was Pentalyn G. The v proportion of the resin-pigmentcomposition added to white enamels A afid B corresponded to 1 gram ofcolored pigment per 200 grams of each enamel.

The results obtained with compositions containing difierent ratios ofresin to pigment are illustrated in the following table;

Cir

grinder vhich yielded a powder of wide particle Table XIV PercentPigment- 10 Percent Resin 90 8O 60 50 v 45 -10 l min Poor Poor Poor PoorPoor Poor Fair Poor Poor d Good Poor Poor K. O. K. O. K. O. K. O. K.Poor Poor K. O. K. O. K. O. K. O. K. Fair Poor K. O. K. O. K. O. K. O.K. Good Poor K. O. K. O. K. O. K. 0. K. Good Poor K. O. K. O. K. O. K.0. K. Good Poor K. O. K. O. K. O. K. O. K. Good Poor EXAMPLE XV sizedistribution. These particles were graded In this example the coloredpigment was Light Chrome Green and the resin was Pentalyn G. Theproportion of the resin-pigment composition added to white enamels A andB corresponded 30 to 2 grams of colored pigment per 200- grams of eachenamel.

The results obtained with compositions containing difierent ratios ofresin to pigment are by shaking through a series of sieves into the meshsizes indicated in the tables in the examples.

Samples of these graded particles were chosen as to contain equalweights of pigment and were stirred into white enamels A and B. Thestir- I" illustrated in the following table: 30

Table XV Percent Pigment 10 20 30 40 5O 60 70 Percent Resin 90 70 60 5040 30 25 l min Poor Poor Poor 2 min Poor Poor Fair 3 min Fair Poor Fair4 min Fair Fair Good 5 in Good Good 0. K. 6min O. K O. O. O. K O. O. K.O. K. O. K. 7 min 0. K. 0. O. 0. K. O. 0. K. O. K. O. K. 8 min O. K. 0.O. O. K. O. 0. K. O. K. O. K. 9 min 0. K. O. K. 0. O. K. 0. K. O. K. O.K. O. K. 10 min 0. K O. K. O. K. O. K 0. K. O. K. O. K. O. K,

The approximate critical ratios of Iresin to pigment in the compositeresin-pigment particles as illustrated by the foregoing examples aresummarized briefly 'in the following table (Table A), which also givesthe approximate particle size of the pigments employed in making thecomposite resin-pigment particles in the foregoing BXalllPlQSj I Table AEXAMPLE XVI In this example the pigment Iron Red was coated with theresin Pentalyn G to give a powdered pigment-resin composition containingParticle (JriticaiResin-Pigment Size of Ratio Pigments l lft y oographic Pcntalyn G Methods I Group I:

Monastral Blue l. 2 89/2l 8/2 Lampblack 08-. 2 7/3 6. 5/3. 5 Group II:

Prussian Blue 2 5/5 5/5 Toluidine Red .2. 3 5/5 4/5 Ferrite Yellow"....25.3 4-5/5-4 3. 5-4/6. 5-6 Titanium Dioxide. 0.3 Group III:

Red Iron Oxide 3-. 45 3/7. 2-3/8-7 Chrome Green-.- .40-. 45 3/7. 2.5-3/7. 5-7 Chrome Yellow 1 41.5 4/6. 7 2. 5-3. 0/7. 5-7

1 Friable, tendency to break to fine particles in'grinding.

75 table:

40% resin and 60% pigment by weight of the total composition. Thiscomposition was then prepared in a variety of particle sizes in themanner previously described, and was mixed with white enamels A and B,each in the proportion of 1.5 grams of pigment per 200 grams of enamel,thereby producing a number of colored enamel samples which were testedfor color development in the manner previously described, with theresults illustrated in the following armies Table XVI Pigment Mesh r 1 NOver 20 20-30 30-40 40-50 50-60 60-80 j 80-100 100-120 120-140 140-200Under Time Poor. Poor Poor Poor Poor Fair Poor Poor Poor Poor Fair FairFair Good Fair Poor Fair Fair Good Good Good Good Good Fair Fair 5 GoodGood 0. K. O. K. Good Good Good Good .K. O. K. 0. K. O. K., 0. K. GoodOJ K. K. O. K. O. K. O. K. O. K. 0. K. 'Good' 0.3:. 0 K. 0.;K. 0. K p.K. 0. K. 0.x. Good 0. K. 0 K. 0. K. O. K. O. K. "0. K. O. K. 0. K. O. K.O. K. 0. K. O..K. O. K. 0. K.I .0. K. O..K.'- 0.35.; 0. K. O. K. O. K.O. K. O.-K. O. K.

Q as will observed,best color development 7 was obtained within acertain range. "Furthermore, within a predetermined range an optimumcolor development .was obtained in a minimum period of time. On theother hand, as the particle size of the resin-pigment compositiondecreased beyond a certain .point the color development also decreased.

EXAMPLE XVII Ina manner similar to that described in Example XV'I, apigment composition containing 80% Pentalyn G and Monastral Blue wastested to determine the effect of particle size on color development anddispersibility characteristics using one gram of pigment per 200 gramsof each of the white enamels A and "B. The results are illustrated inthe following table:

XI with Table VI, .it will 'be observed that although in Table XIthelres'in to pigment ratio was not carried below 65% to in Table VI theratio was carried to a lower resin to pigment ratio with the samepigment and the color development began to drop sharply. "In a similarmanner, Table XV may be compared with Table VII. "The results in thetables clearly illustrate that there is a predetermined minimum ratio ofresin to pigment required for the purpose of the invention.

The expression predetermined relatively large ratios of resin to pigmentrefers to percentage ratios of the type described in this specification,taking into account the different types of pigments. In all cases theseratios are relatively large ascompared with resin to pigment ratios thathad been used before for most purposes.

TabZeXVII Pigment Mesh 1 H Q N0 Over 20v 20-30 30-40 40-"50 -60 00-8080-100 100-120 120-140 140-2010 Under r 200 Time Poor Poor Poor PoorPoor 1 'Fair Fair Fair Fair Fai F Poor Poor Poor. Poor Fair 2 Good Good-Good Good Poor Poor Poor Poor Good. 0. K. O. K. O. K. Good Fair FairPoor Poor Poor Fair 0. K. j 0. K. 0. K. O. K. O. K. Fair Fair Poor .Poor3 Fair Good 0. -.K. 0. K. 0. K. O. K. x 0.1!. Good Good Poor Poor FairGood ,0. K. 0.,K. 0. K. 0. K. O. K. Good Good Poor Fair Good. 0. K. O.K. O. K. O. K. 0. K. 0. K. Good Good Poor Fair 30. K. 0. K. 0. K. I 0.K. O. K. O. K. O. K; Good Good Poor Fair O. K. O. K. O. ;K. 0. K. O. K.O. K. O. K. Good Good Poor Fair 0-. K. 0. K. 0. K. O. K. O. K. 0. K. O.K. 0. K. Good Again it was shown, as in Example that the particle sizeof the resin-pigment composition affected the results obtained "within arange which could be predetermined. .Also. it was observed that thisrange was approximately the same as that in Example XVI, the optimumresultsin each case being outlined withla composite resin-pigment havinga particle size between 40 and 200 mesh, and preferably from about 5.0to 140v mesh (calculated as square openings per square inch).

The following TableZB summarizes the results of Examples XVI and XVII:Table B.-Particle size of composite resingp'igment particles requiredfor full-color development by manual stirring .s-Minj 4Min.i sJMm.

Pental G-Ptedlron Oxide... sonic ..c0 2no Pentely G-Monastral Blue-60-'l20 50-140 50-140 1 but in-each such instance these results areillustrated by other tables. Thus, in comparing Table The requiredratios, however, as already demonstrated, are greater with some types ofpigment than with others. Thus, with pigments approximating the surfaceand density characteristics of 'Monastral Blue Copper 'Phthalocyan'ine),the predetermined critical minimum ratio of resin to pigmentapproximates 65% resin to 35% pigment, and theoptimum or preferred ratioapproximates resin to 15% "pigment. With pigments approximating thesurface and density characteristics of Iron Blue (Prussian Blue), thepredetermined critical minimum 'ratio of resin to pigment isapproximately "50% resin to 50% pigment, and the optimum or preferredratio is about 70% resin to 30% pigment. With"'the heavier types ofpigments approximating the physical characteristics of Chrome Green, thepredetermined minimum ratio of resin to pigment approximates "20% to 25%resin to "75%- 80% pigment, and the optimum or preferred ratioapproximates 40% resin to 60% pigment. The minimum ratio of resin topigment is limited largely by practical considerations and-canbe as highas resin to 10% pigment, although in most instances the optimum resultsare obtained at a lower ratio of resin to pigment, and therefore, itwould be uneconomical to employ larger percentages of-resin than thoseatwlfilch the optimum results are obtained. 0

The results given in the examples illustrate that the invention isapplicable to all types of pigments. It is applicable not only tocolored pigment, but also to white pigments. The white pigments can beemployed in about the same manner as the colored pigments except thatwhereas the colored pigments require only several grams of pigment pergallon of coating composition, the white pigments may require as much asfour pounds of pigment per gallon.

The invention is not-limited to the use of any particular resin forcoating the pigment particles. The resin should be one which will form acoating or film on the pigment particles; it should have arelatively'high melting point so as to be substantially non-softeningunder conditions of storage and use; it should preferably be afilm-forming resin which is preferably insoluble in water and soluble inaliphatic hydrocarbon solvents, and it must be soluble in the vehicle inwhich the powdered resin-pigment composition is to be dispersed.Excellent results have been obtained with the two types ofjresi'ns givenin the examples. Other' illustrations of suitable resins are Congo esterand ester gum.

The invention is not limited to any particular manner or means forcoating the discrete pigment particles with the resin. The method andapparatus described with respect to the examples gives very satisfactoryresults, butother methods and apparatus may be used.

The examples also illustrate the application of the invention to two ofthe principal types of vehicles employed in making pigmented coatingcompositions, namely, oleoresinous varnishes and alkyd resin vehicles.The invention is not limited to these two types of, vehicles, but mayalso be employed with other liquid vehicles having suitable drying,film-forming and/or other qualities, depending upon the desired use ofthe product. Thus, to prepare a house paint the resinpigment compositionwould be mixed with linseed oil or other type of oil suitable for thispurpose; to prepare a fiat wall or semi-gloss finish it would be mixedwith an oleoresinous varnish; to prepare an automotive finish it wouldbe mixed with an alkyd varnish; and to prepare a pigmented lacquer itwould be mixed with a nitrocellulose or other lacquer of this type.According'ly, the invention is applicable generally to the preparationof pigmented coating compositions. "The vehicle to which the powderedresin-pigment composition is added may be a clear vehicle or a.pigmented vehicle. Excellent results are obtained in either case. Theinvention is particu: larly important, however, where the powderedresin-pigment composition is added to apigmente'd vehicle such as awhite enamel. In this manner the white enamel canbe used as a base forany desired color. All it requires is the addition of the powderedresin-pigment composition which provides the color, the principalcovering power being supplied by the base enamel.

The examples indicate that the desirable ratio of resin to pigment issomewhat dependent upon theresin employed. The use of different types ofresins, however, does not substantially change the critical minimumratios for the various types ofpigments.

Infthe practice of the invention, auxiliary substances suchyas mica orother anti-bonding or anti-blocking-agents can be added to the composite resin-pigment particlespreferably after they have been screenedto :size. These substances are adapted to-prevent sticking, and in somecases the use of such substances will permit the use of resins having asomewhat lower melting point. Other examples of suitable anti 'bondingagents are whiting, chalk, talc, starch and similar materials. Thequantity employed should preferably be about 5% to 10% by weight of thecomposite pigment. Larger amounts are usually unnecesary and merely havea diluting effect. The preferred type of anti-bonding agent is a finelyground or micronized mica.

jDispersing and wetting agents may be incorporated with the compositeresin-pigment particles but are not considered necessary.

7 The invention provides a new system or method for'handling andpreparing all types of pigmented coating compositions, including paints,enamels and lacquers. Instead of the pigment being-incorporated into thevehicle by the manufacturer as is customary atpresent, the pigment andthe vehicle are supplied separately as a plural component ormulti-component product, the pigment being supplied in the form of arelatively small package of the powdered resin-pigment composition andthe vehicle being supplied either as a clear base or a pigmented basevehicle, in whichthe resin. of the powdered resin-pigment composition issoluble.

The powdered resin-pigment composition is free flowing, non-sticky, anddisperses in the vehicle merely by hand stirring in a relatively shortperiod of time, say from 2 to 10 minutes, the time varying somewhatdepending upon the quantitybeing'mixed. During this dispersion theresin. of the powdered resin-pigment composition dissolves in thevehicle, liberating individual pigment particles which attain full colordevelopment. The invention provides compositions which produce thedesired result with th minimum formation of agglomerated particles suchas cause streaks when the resultant pigmented coating composition isapplied. The fact that the use of a relatively large amount of resin inpreparingthe powdered resin-pigment compositiorrcontributes to these newand improved results-issurprising, since a thin coating of resin on thepigment particles might be expected to produce a more rapid solution ofresin, and hence a more rapid dispersion and color development of thepigment.

A further, important advantage of the invention resides in the fact thatno apparatus is required to disperse theJpowdered.resin-pigmentcomposition :inthe vehicle. The grinding methods heretofore employed.for incorporating the pigmentinto the vehicle are replaced by simplehand or manual stirring. No expert handling is required because all thatis necessary is to mix manually a package of the powdered pigmentcomposition containing a predetermined quantity thereof with apredetermined quantity of the vehicle. 3

. The invention makes it possible to reduce the amount of liquid vehiclerequired to be tied up in storage, especially on retail stores shelves,as compared to present day requirements. It reduces the initial-expenseof the retailer in building up an inventory, it reduces the carryingcharges, and greatly reduces storage space requirements, therebyresulting in an over-all saving to the consumer. The screen sizes giventhroughout the specification and claims refer to the United States Sieveseries of the United States Bureau ofStandards (1919) series.

This case as well as copending applications of- U. S. gSeria'l No.152,764 andU. S. Serial No.

5 filed o evennate, ar t n m parta' to common subject matter- 1 a1 1% ilJanuary 17, 194

doned'.

Havingtlms .describedthe inventio claim ja fiewand desire; secure byLetters Patent ofthe' United States isi' l. A method ofpreparingapigmented composition which comprises "dispersing a colored.pigment in resin} the pigment fcharafcterized'.

by an average particle diameter of namdz to 0.3

micron, said Jesin friableat a C; but plast at elevated temperatures andsoluble in Q1891 resinous varnishes, dispersinglfsaid pigm'eri in saidresinliwhile the resin is and saifp gfnent constituting a not more than50% by weig ment-in-resin mixture, thereafter cooling the pigment-resindispersion to a temperature at which the resin is friable. andpulverizing, classifying and retaining the particles of the resultantcolor concentrate passing through a 40 mesh screen and withheld on a 200mesh screen.

2. A granular color concentrate useful to change the coloration of aliquid paint system in a uniform manner through manual incorporationtherein which comprises a pigmented resin, drypowdered, the coloredpigment characterized by an average particle diameter of from 0.2 to 0.3micron, dispersed in a resin friable at 20 C., but plastic at elevatedtemperatures-and soluble in oleoresinous varnishes, said pigmentconstituting at least but not more than 50% by weight of the totalpigment-in-resin dispersion, and said solid concentrate classified inparticle size to pass through a 40 mesh screen and withheld on a 200mesh screen.

3. A method of preparing a pigmented composition which comprisesdispersing a pigment in a resin, the pigment selected from the groupconsisting of iron blue, toluidine red, ferrite yellow and titaniumdioxide, the resin friable at 20 C. but plastic at elevated temperaturesand soluble in oleoresinous varnishes, dispersing said pig ment in saidresin while the resin is in a plastic state, said pigment constitutingat least 25% but not more than 50% by weight of the totalpigment-in-resin mixture, thereafter cooling the pigment-resindispersion to a temperature at which the resin is friable andpulverizing, classifying and retaining the particles of the resultantcolor concentrate passing through a 40 mesh screen and withheld on a 200mesh screen.

4. A method of preparing a pigmented composition which comprisesdispersing a pigment in a resin, the pigment selected from the groupconsisting of iron blue, toluidine red, ferrite yellow, and titaniumdioxide, each of said pigments having an average particle diameter offrom 0.2 to 0.3 micron, the resin friable at room temperature butplastic at elevated temperatures and soluble in oleoresinous varnishes,dispersing said pigment in said resin while the resin is in a plasticstate, said pigment constituting at least 25 but not more than 50% byweight of the total pigment-in-resin mixture, thereafter cooling thepigment-resin dispersion to a temperature at which the ersin is friable,and pulverizing, classifying and retaining the particles of theresultant color concentrate passing through a 50 mesh screen andwithheld on a 140 mesh screen.

5. A method of preparing a pigmented composition which comprisesdispersing a pigment in a resin, said pigment being an iron blue havingan average particle diameter of from 0.2 to 0.3

' ferrite" "yellow.

' sw t 8. Same as claim 5, wherein the pigment is titanium dioxide.

9. A method of preparing a pigmented composition which comprisesdispersing a pigment in a resin, said pigment selected from the groupconsisting of iron blue, toluidine red, ferrite yellow, and titaniumdioxide, each of said pigments having an average particle diameter offrom 0.2

to 0.3 micron, said resin friable at 20 C. but

plastic at elevated temperatures and soluble in oleoresinous varnishes,dispersing said pigment in said resin while the resin is-in a plasticstate, said pigment constituting at least 25% but not more than 35% byweight of the total pigmentin-resin mixture, thereafter cooling saidpigment-resin dispersion to a temperature at which the resin is friable,and pulverizing, classifying and retaining the particles of theresultant color concentrate passing through a mesh screen and withheldon a 140 mesh screen.

10. A method of preparing a pigmented composition which comprisesdispersing a pigment in a resin, said pigment being an iron blue havingan average particle diameter of from 0.2 to 0.3 micron, and said resinfriable at 20 C. but plastic at elevated temperatures and soluble inoleoresinous varnishes, dispersing said pigment in said resin while theresin is in a plastic state,

said pigment constituting at least 25% but not more than 35% by weightof the total pigmentin-resin mixture, thereafter cooling saidpigment-resin dispersion to a temperature at which the resin is friable,and pulverizing, classifying and retaining the particles of theresultant color concentrate passing through a ,50 mesh screen andwithheld on a mesh screen.

11. Same as claim 10, wherein the pigment is toluidine red. I

12. Same as claim 10, wherein the pigment is ferrite yellow.

13. Same as claim 10, wherein the pigment is titanium dioxide.

14. A granular color concentrate useful to change the coloration of a.liquid paint system in a uniform manner through manual incorporationtherein which comprises a pigmented resin, dry-powdered, the pigmentaryportion selected from the group consisting of iron blue, toluidine red,ferrite yellow and titanium dioxide, each of said pigments having anaverage particle diameter of from 0.2 to 0.3 micron, dispersed in afriable but thermoplastic resin soluble in oleoresinous varnishes, saidpigment constituting from- 25% to not more than 35% by weight of thetotal pigment-in-resin dispersion, and said solid concentratepreferentially classified in particle size to pass through a 50 meshscreen and be retained on a 140 mesh screen.

15. A granular color concentrate useful to hnge the wa mth orv a liquidpaint system in" a uniform manner through manualincorporationth'ereinflwhich comprises a, pigmented resin,

drypowderdr the pigmentary portion being an iron blue having an averageparticle diameter of from 0.2' to 0.3 micron, dispersed in a resinfriable at C., but plastic at elevated temperatures and soluble'in'oleoresinous varnishesgsaid pigment constituting from to not more thanbyweight of the total pigment-in-re'sindispersion, and said solidconcentrate preferential-- 1y classified in particle size toctzvmpletely pass through a mesh screen and be retainedon a 200 meshscreen.

16. Same as claim 15, where theipigment is 15 toluidine red.

i 20 17,, vSame-"asjclaim' 15,-'where the pigment is mate yenom I 4 18.Same as claim 15, where the'pigmentds titanium dioxide. t t

I 'WILLIAM T. WALTON.

" AR'IHUR B. HOLTON.

REFERENCES CITED Thefollowing references are of record in the 10 me ofthis patent:

UNITED STATES BATENTS' Number, Name Date 2,000,003 Verbyla. Apr. 30,19352,244,020 Patton June a, 1941 3,379,237 Jenkins June 26. 1945

14. A GRANULAR COLOR CONCENTRATE USEFUL TO CHANGE THE COLORATION OF ALIQUID PAINT SYSTEM IN A UNIFORM MANNER THROUGH MANUAL INCORPORATIONTHEREIN WHICH COMPRISES A PIGMENTED RESIN, DRY-POWDERED, THE PIGMENTARYPORTION SELECTED FROM THE GROUP CONSISTING OF IRON BLUE TOLUIDINE RED,FERRIT YELLOW AND TITANIUM DIOXIDE, EACH OF SAID PIGMENTS HAVING ANAVERAGE PARTICLE DIAMETER OF FROM 0.2 TO 0.3 MICRON, DISPERSED IN AFRIABLE BUT THERMOPLASTIC RESIN SOLUBLE IN OLEORESINOUS VARNISHES, SAIDPIGMENT CONSTITUTING FROM 25% TO NOT MORE THAN 35% BY WEIGHT OF THETOTAL PIGMENT-IN-RESIN DISPERSION, AND SAID SOLID CONCENTRATEPREFERENTIALLY CLASSIFIED IN PARTICLE SIZE TO PASS THROUGH A 50 MESHSCREEN AND BE RETAINED ON A 140 MESH SCREEN.